Game ball delivery apparatus are a common means for enhanced practice and instruction of sports such as tennis, baseball, soccer, and table tennis. The game ball delivery apparatus sequentially ejects game balls such that a player can practice by returning the balls as if playing with an opponent or instructor. To enable the player to practice a variety of strokes, the game ball delivery apparatus may allow the user to select from options that control the trajectories of the game balls, such as the direction, speed, and interval between successive balls. The game ball delivery apparatus may allow the user to set such options for each ball or to select from a set of programs pre-defined by the manufacturer of the apparatus. For example, a tennis ball delivery apparatus may provide a program that challenges the player to alternate between forehand strokes and backhand strokes. U.S. Pat. No. 4,269,163 details a game ball delivery apparatus that allows a user to select from such pre-defined options and programs.
Providing such pre-defined options and programs allows the user to select the program that the user considers most desirable for their current practice needs. However, the apparatus is limited to the pre-defined options established by the manufacturer, and those pre-defined options may not reflect the actual needs of the player. Additionally players using such machines are required to determine which pre-defined options would be most beneficial to improving their skill. It would be desirable to have a game ball delivery apparatus that could sense the player's performance ability, and adapt the delivery of game balls according to the actual practice needs of that specific player.
U.S. Pat. No. 4,915,384 describes a player adaptive sports training system that includes a target for which the player should aim when returning a delivered ball. The system described by U.S. Pat. No. 4,915,384 is capable of detecting whether the player hits said target with returned ball and of adjusting parameters, such as delivered ball speed or target to meet the skill level of that player. Thus, U.S. Pat. No. 4,915,384 adapts game ball delivery to current ability of the player to hit a target, as opposed to identifying the player's weaknesses and adapting the program to eliminate those weaknesses. Also, U.S. Pat. No. 4,915,384 is limited by sensing only if a target is hit and not sensing the player's actual motions, and thus not detecting whether the player is using proper movements and orientations. For example, in the game of baseball, hitting a ball such that it is easily caught before touching the ground (commonly referred to as a pop fly) is undesirable even if it does reach a target. It would be desirable to have the game ball delivery apparatus sense the player's orientation and movements, to detect conditions under which the player is not performing optimally, and to adjust the game ball delivery program to concentrate the player's practice program on eliminating weaknesses and refining their technique.
U.S. Pat. No. 5,816,953 describes an interactive apparatus that senses where the player's returned ball lands such that it can display the returned position on a video screen, but also does not adapt the delivery of balls based on this information.
Therefore, there exists a need for an apparatus capable of adapting game ball delivery based on player-specific performance data, such as the player's orientation and movements.